System and method for percutaneously administering reduced pressure treatment using a flowable manifold

ABSTRACT

A reduced pressure delivery system for applying a reduced pressure to a tissue site includes a manifold delivery tube having a passageway and a distal end, the distal end configured to be percutaneously inserted and placed adjacent the tissue site. A flowable material is provided and is percutaneously deliverable through the manifold delivery tube to the tissue site. The flowable material is capable of filling a void adjacent the tissue site to create a manifold having a plurality of flow channels in fluid communication with the tissue site. A reduced pressure delivery tube is provided that is capable of fluid communication with the flow channels of the manifold.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 11/724,073, filed Mar. 13, 2007, now U.S. Pat. No. 8,267,918,entitled, “SYSTEM AND METHOD FOR PERCUTANEOUSLY ADMINISTERING REDUCEDPRESSURE TREATMENT USING A FLOWABLE MANIFOLD, which claims the benefit,under 35 USC §119(e), of the filing of U.S. Provisional Application No.60/782,171, filed Mar. 14, 2006, the disclosure of which is herebyincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to a system or method of promotingtissue growth and more specifically a system for applying reducedpressure tissue treatment to a tissue site.

2. Description of Related Art

Reduced pressure therapy is increasingly used to promote wound healingin soft tissue wounds that are slow to heal or non-healing withoutreduced pressure therapy. Typically, reduced pressure is applied to thewound site through an open-cell foam that serves as a manifold todistribute the reduced pressure. The open-cell foam is sized to fit theexisting wound, placed into contact with the wound, and thenperiodically replaced with smaller pieces of foam as the wound begins toheal and become smaller. Frequent replacement of the open-cell foam isnecessary to minimize the amount of tissue that grows into the cells ofthe foam. Significant tissue in-growth can cause pain to patients duringremoval of the foam.

Reduced pressure therapy is typically applied to non-healing, openwounds. In some cases, the tissues being healed are subcutaneous, and inother cases, the tissues are located within or on dermal tissue.Traditionally, reduced pressure therapy has primarily been applied tosoft tissues. Reduced pressure therapy has not typically been used totreat closed, deep-tissue wounds because of the difficulty of accesspresented by such wounds. Additionally, reduced pressure therapy has notbeen used in connection with healing bone defects or promoting bonegrowth, primarily due to access problems. Surgically exposing a bone toapply reduced pressure therapy may create more problems than it solves.Finally, devices and systems for applying reduced pressure therapy haveadvanced little beyond the open-cell foam pieces that are manuallyshaped to fit a wound site and then removed following a period ofreduced pressure therapy.

BRIEF SUMMARY OF THE INVENTION

The problems presented by existing wound-healing system and methods aresolved by the systems and methods of the present invention. A reducedpressure delivery system is provided in accordance with one embodimentof the present invention to apply a reduced pressure to a tissue site.The reduced pressure delivery system includes a manifold delivery tubehaving a passageway and a distal end, the distal end configured to bepercutaneously inserted and placed adjacent the tissue site. A flowablematerial is percutaneously deliverable through the manifold deliverytube to the tissue site such that the flowable material is capable offilling a void adjacent the tissue site to create a manifold having aplurality of flow channels in fluid communication with the tissue site.A reduced pressure delivery tube is provided that is capable of fluidcommunication with the flow channels of the manifold.

In accordance with another embodiment of the present invention, a methodof administering a reduced pressure therapy to a tissue site is providedand includes percutaneously positioning a distal end of a manifolddelivery tube adjacent a tissue site. A flowable material ispercutaneously delivered through the manifold delivery tube to thetissue site. The flowable material is capable of filling a void adjacentthe tissue site to create a manifold having a plurality of flow channelsin fluid communication with the tissue site. A reduced pressure isapplied to the tissue site through the flow channels of the manifold.

Other objects, features, and advantages of the present invention willbecome apparent with reference to the drawings and detailed descriptionthat follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee.

FIG. 1 depicts a perspective view of a reduced pressure deliveryapparatus according to an embodiment of the present invention, thereduced pressure delivery apparatus having a plurality of projectionsextending from a flexible barrier to create a plurality of flowchannels;

FIG. 2 illustrates a front view of the reduced pressure deliveryapparatus of FIG. 1;

FIG. 3 depicts a top view of the reduced pressure delivery apparatus ofFIG. 1;

FIG. 4A illustrates a side view of the reduced pressure deliveryapparatus of FIG. 1, the reduced pressure delivery apparatus having asingle lumen, reduced-pressure delivery tube;

FIG. 4B depicts a side view of an alternative embodiment of the reducedpressure delivery apparatus of FIG. 1, the reduced pressure deliveryapparatus having a dual lumen, reduced-pressure delivery tube;

FIG. 5 illustrates an enlarged perspective view of the reduced pressuredelivery apparatus of FIG. 1;

FIG. 6 depicts a perspective view of a reduced pressure deliveryapparatus according to an embodiment of the present invention, thereduced pressure delivery apparatus having a cellular material attachedto a flexible barrier having a spine portion and a pair of wingportions, the cellular material having a plurality of flow channels;

FIG. 7 illustrates a front view of the reduced pressure deliveryapparatus of FIG. 6;

FIG. 8 depicts a cross-sectional side view of the reduced pressuredelivery apparatus of FIG. 7 taken at XVII-XVII;

FIG. 8A illustrates a cross-sectional front view of a reduced pressuredelivery apparatus according to an embodiment of the present invention;

FIG. 8B depicts a side view of the reduced pressure delivery apparatusof FIG. 8A;

FIG. 9 illustrates a front view of a reduced pressure delivery apparatusaccording to an embodiment of the present invention being used to applya reduced pressure tissue treatment to a bone of a patient;

FIG. 10 depicts a color histological section of a rabbit cranium showingnaive, undamaged bone;

FIG. 11 illustrates a color histological section of a rabbit craniumshowing induction of granulation tissue after application of reducedpressure tissue treatment;

FIG. 12 depicts a color histological section of a rabbit cranium showingdeposition of new bone following application of reduced pressure tissuetreatment;

FIG. 13 illustrates a color histological section of a rabbit craniumshowing deposition of new bone following application of reduced pressuretissue treatment;

FIG. 14 depicts a color photograph of a rabbit cranium having twocritical size defects formed in the cranium;

FIG. 15 illustrates a color photograph of the rabbit cranium of FIG. 14showing a calcium phosphate scaffold inserted within one of the criticalsize defects and a stainless steel screen overlaying the second of thecritical size defects;

FIG. 16 depicts a color photograph of the rabbit cranium of FIG. 14showing the application of reduced pressure tissue treatment to thecritical size defects;

FIG. 17 illustrates a color histological section of a rabbit craniumfollowing reduced pressure tissue treatment, the histological sectionshowing deposition of new bone within the calcium phosphate scaffold;

FIG. 18 depicts a radiograph of the scaffold-filled, critical sizedefect of FIG. 15 following six days of reduced pressure tissuetreatment and two weeks post surgery;

FIG. 19 illustrates a radiograph of the scaffold-filled, critical sizedefect of FIG. 15 following six days of reduced pressure tissuetreatment and twelve weeks post surgery;

FIG. 20 depicts a front view of a reduced pressure delivery systemaccording to an embodiment of the present invention, the reducedpressure delivery system having a manifold delivery tube that is used topercutaneously insert a reduced pressure delivery apparatus to a tissuesite;

FIG. 21 illustrates an enlarged front view of the manifold delivery tubeof FIG. 20, the manifold delivery tube containing a reduced pressuredelivery apparatus having a flexible barrier and/or a cellular materialin a compressed position;

FIG. 22 depicts an enlarged front view of the manifold delivery tube ofFIG. 21, the flexible barrier and/or cellular material of the reducedpressure delivery apparatus being shown in an expanded position afterhaving been pushed from the manifold delivery tube;

FIG. 23 illustrates a front view of a reduced pressure delivery systemaccording to an embodiment of the present invention, the reducedpressure delivery system having a manifold delivery tube that is used topercutaneously insert a reduced pressure delivery apparatus to a tissuesite, the reduced pressure delivery apparatus being shown outside of themanifold delivery tube but constrained by an impermeable membrane in acompressed position;

FIG. 24 depicts a front view of the reduced pressure delivery system ofFIG. 23, the reduced pressure delivery apparatus being shown outside ofthe manifold delivery tube but constrained by an impermeable membrane ina relaxed position;

FIG. 25 illustrates a front view of the reduced pressure delivery systemof FIG. 23, the reduced pressure delivery apparatus being shown outsideof the manifold delivery tube but constrained by an impermeable membranein an expanded position;

FIG. 25A illustrates a front view of the reduced pressure deliverysystem of FIG. 23, the reduced pressure delivery apparatus being shownoutside of the manifold delivery tube but surrounded by an impermeablemembrane in an expanded position

FIG. 26 depicts a front view of a reduced pressure delivery systemaccording to an embodiment of the present invention, the reducedpressure delivery system having a manifold delivery tube that is used topercutaneously insert a reduced pressure delivery apparatus to a tissuesite, the reduced pressure delivery apparatus being shown outside of themanifold delivery tube but constrained by an impermeable membrane havinga glue seal;

FIG. 26A depicts a front view of a reduced pressure delivery systemaccording to an embodiment of the present invention;

FIG. 27 illustrates a front view of a reduced pressure delivery systemaccording to an embodiment of the present invention, the reducedpressure delivery system having a manifold delivery tube that is used topercutaneously inject a reduced pressure delivery apparatus to a tissuesite;

FIG. 27A illustrates a front view of a reduced pressure delivery systemaccording to an embodiment of the present invention, the reducedpressure delivery system having a manifold delivery tube that is used topercutaneously deliver a reduced pressure delivery apparatus to animpermeable membrane positioned at a tissue site;

FIG. 28 depicts a flow chart of a method of administering a reducedpressure tissue treatment to a tissue site according to an embodiment ofthe present invention;

FIG. 29 illustrates a flow chart of a method of administering a reducedpressure tissue treatment to a tissue site according to an embodiment ofthe present invention;

FIG. 30 depicts a flow chart of a method of administering a reducedpressure tissue treatment to a tissue site according to an embodiment ofthe present invention;

FIG. 31 illustrates a flow chart of a method of administering a reducedpressure tissue treatment to a tissue site according to an embodiment ofthe present invention;

FIG. 32 depicts a cross-sectional front view of a reduced pressuredelivery apparatus according to an embodiment of the present invention,the reduced pressure delivery apparatus including a hip prosthesishaving a plurality of flow channels for applying a reduced pressure toan area of bone surrounding the hip prosthesis;

FIG. 33 illustrates a cross-sectional front view of the hip prosthesisof FIG. 32 having a second plurality of flow channels for delivering afluid to the area of bone surrounding the hip prosthesis;

FIG. 34 depicts a flow chart of a method for repairing a joint of apatient using reduced pressure tissue treatment according to anembodiment of the present invention;

FIG. 35 illustrates a cross-sectional front view of a reduced pressuredelivery apparatus according to an embodiment of the present invention,the reduced pressure delivery apparatus including a orthopedic fixationdevice having a plurality of flow channels for applying a reducedpressure to an area of bone adjacent the orthopedic fixation device;

FIG. 36 depicts a cross-sectional front view of the orthopedic fixationdevice of FIG. 35 having a second plurality of flow channels fordelivering a fluid to the area of bone adjacent the orthopedic fixationdevice;

FIG. 37 illustrates a flow chart of a method for healing a bone defectof a bone using reduced pressure tissue treatment according to anembodiment of the present invention;

FIG. 38 depicts a flow chart of a method of administering a reducedpressure tissue treatment to a tissue site according to an embodiment ofthe present invention; and

FIG. 39 illustrates a flow chart of a method of administering a reducedpressure tissue treatment to a tissue site according to an embodiment ofthe present invention.

FIGS. 40-48 depict various views of a reduced pressure delivery systemaccording to an embodiment of the present invention, the reducedpressure delivery system having a primary manifold that includes aflexible wall surrounding a primary flow passage and a plurality ofapertures in the flexible wall;

FIGS. 49-50 illustrate perspective and top cross-sectional views of areduced pressure delivery system according to an embodiment of thepresent invention, the reduced pressure delivery system having a primarymanifold that is integrally connected to a reduced pressure deliverytube;

FIG. 51 depicts a perspective view of the primary manifolds of FIGS.40-50 being applied with a secondary manifold to a bone tissue site; and

FIG. 52 illustrates a schematic view of a reduced pressure deliverysystem having a valve fluidly connected to a second conduit according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration specific preferredembodiments in which the invention may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention, and it is understood that other embodiments maybe utilized and that logical structural, mechanical, electrical, andchemical changes may be made without departing from the spirit or scopeof the invention. To avoid detail not necessary to enable those skilledin the art to practice the invention, the description may omit certaininformation known to those skilled in the art. The following detaileddescription is, therefore, not to be taken in a limiting sense, and thescope of the present invention is defined only by the appended claims.

As used herein, the term “elastomeric” means having the properties of anelastomer. The term “elastomer” refers generally to a polymeric materialthat has rubber-like properties. More specifically, most elastomers haveelongation rates greater than 100% and a significant amount ofresilience. The resilience of a material refers to the material'sability to recover from an elastic deformation. Examples of elastomersmay include, but are not limited to, natural rubbers, polyisoprene,styrene butadiene rubber, chloroprene rubber, polybutadiene, nitrilerubber, butyl rubber, ethylene propylene rubber, ethylene propylenediene monomer, chlorosulfonated polyethylene, polysulfide rubber,polyurethane, and silicones.

As used herein, the term “flexible” refers to an object or material thatis able to be bent or flexed. Elastomeric materials are typicallyflexible, but reference to flexible materials herein does notnecessarily limit material selection to only elastomers. The use of theterm “flexible” in connection with a material or reduced pressuredelivery apparatus of the present invention generally refers to thematerial's ability to conform to or closely match the shape of a tissuesite. For example, the flexible nature of a reduced pressure deliveryapparatus used to treat a bone defect may allow the apparatus to bewrapped or folded around the portion of the bone having the defect.

The term “fluid” as used herein generally refers to a gas or liquid, butmay also include any other flowable material, including but not limitedto gels, colloids, and foams.

The term “impermeable” as used herein generally refers to the ability ofa membrane, cover, sheet, or other substance to block or slow thetransmission of either liquids or gas. Impermeability may be used torefer to covers, sheets, or other membranes that are resistant to thetransmission of liquids, while allowing gases to transmit through themembrane. While an impermeable membrane may be liquid tight, themembrane may simply reduce the transmission rate of all or only certainliquids. The use of the term “impermeable” is not meant to imply that animpermeable membrane is above or below any particular industry standardmeasurement for impermeability, such as a particular value of watervapor transfer rate (WVTR).

The term “manifold” as used herein generally refers to a substance orstructure that is provided to assist in applying reduced pressure to,delivering fluids to, or removing fluids from a tissue site. A manifoldtypically includes a plurality of flow channels or pathways that areinterconnected to improve distribution of fluids provided to and removedfrom the area of tissue around the manifold. Examples of manifolds mayinclude without limitation devices that have structural elementsarranged to form flow channels, cellular foam such as open-cell foam,porous tissue collections, and liquids, gels and foams that include orcure to include flow channels.

The term “reduced pressure” as used herein generally refers to apressure less than the ambient pressure at a tissue site that is beingsubjected to treatment. In most cases, this reduced pressure will beless than the atmospheric pressure at which the patient is located.Alternatively, the reduced pressure may be less than a hydrostaticpressure of tissue at the tissue site. Although the terms “vacuum” and“negative pressure” may be used to describe the pressure applied to thetissue site, the actual pressure applied to the tissue site may besignificantly less than the pressure normally associated with a completevacuum. Reduced pressure may initially generate fluid flow in the tubeand the area of the tissue site. As the hydrostatic pressure around thetissue site approaches the desired reduced pressure, the flow maysubside, and the reduced pressure is then maintained. Unless otherwiseindicated, values of pressure stated herein are gage pressures.

The term “scaffold” as used herein refers to a substance or structureused to enhance or promote the growth of cells and/or the formation oftissue. A scaffold is typically a three dimensional porous structurethat provides a template for cell growth. The scaffold may be infusedwith, coated with, or comprised of cells, growth factors, or othernutrients to promote cell growth. A scaffold may be used as a manifoldin accordance with the embodiments described herein to administerreduced pressure tissue treatment to a tissue site.

The term “tissue site” as used herein refers to a wound or defectlocated on or within any tissue, including but not limited to, bonetissue, adipose tissue, muscle tissue, neural tissue, dermal tissue,vascular tissue, connective tissue, cartilage, tendons, or ligaments.The term “tissue site” may further refer to areas of any tissue that arenot necessarily wounded or defective, but are instead areas in which itis desired to add or promote the growth of additional tissue. Forexample, reduced pressure tissue treatment may be used in certain tissueareas to grow additional tissue that may be harvested and transplantedto another tissue location.

Referring to FIGS. 1-5, a reduced pressure delivery apparatus, or wingmanifold 211 according to the principles of the present inventionincludes a flexible barrier 213 having a spine portion 215 and a pair ofwing portions 219. Each wing portion 219 is positioned along oppositesides of the spine portion 215. The spine portion 215 forms an arcuatechannel 223 that may or may not extend the entire length of the wingmanifold 211. Although the spine portion 215 may be centrally located onthe wing manifold 211 such that the width of the wing portions 219 isequal, the spine portion 215 may also be offset as illustrated in FIGS.1-5, resulting in one of the wing portions 219 being wider than theother wing portion 219. The extra width of one of the wing portions 219may be particularly useful if the wing manifold 211 is being used inconnection with bone regeneration or healing and the wider wing manifold211 is to be wrapped around fixation hardware attached to the bone.

The flexible barrier 213 is preferably formed by an elastomeric materialsuch as a silicone polymer. An example of a suitable silicone polymerincludes MED-6015 manufactured by Nusil Technologies of Carpinteria,Calif. It should be noted, however, that the flexible barrier 213 couldbe made from any other biocompatible, flexible material. The flexiblebarrier 213 encases a flexible backing 227 that adds strength anddurability to the flexible barrier 213. The thickness of the flexiblebarrier 213 encasing the flexible backing 227 may be less in the arcuatechannel 223 than that in the wing portions 219. If a silicone polymer isused to form the flexible barrier 213, a silicone adhesive may also beused to aid bonding with the flexible backing 227. An example of asilicone adhesive could include MED-1011, also sold by NusilTechnologies. The flexible backing 227 is preferably made from apolyester knit fabric such as Bard 6013 manufactured by C.R. Bard ofTempe, Ariz. However, the flexible backing 227 could be made from anybiocompatible, flexible material that is capable of adding strength anddurability to the flexible barrier 213. Under certain circumstances, ifthe flexible barrier 213 is made from a suitably strong material, theflexible backing 227 could be omitted.

It is preferred that either the flexible barrier 213 or the flexiblebacking 227 be impermeable to liquids, air, and other gases, oralternatively, both the flexible backing 227 and the flexible barrier213 may be impermeable to liquids, air, and other gases.

The flexible barrier 213 and flexible backing 227 may also beconstructed from bioresorbable materials that do not have to be removedfrom a patient's body following use of the reduced pressure deliveryapparatus 211. Suitable bioresorbable materials may include, withoutlimitation, a polymeric blend of polylactic acid (PLA) and polyglycolicacid (PGA). The polymeric blend may also include without limitationpolycarbonates, polyfumarates, and capralactones. The flexible barrier213 and the flexible backing 227 may further serve as a scaffold for newcell-growth, or a scaffold material may be used in conjunction with theflexible barrier 213 and flexible backing 227 to promote cell-growth.Suitable scaffold material may include, without limitation, calciumphosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, orprocessed allograft materials. Preferably, the scaffold material willhave a high void-fraction (i.e. a high content of air).

In one embodiment the flexible backing 227 may be adhesively attached toa surface of the flexible barrier 213. If a silicone polymer is used toform the flexible barrier 213, a silicone adhesive may also be used toattach the flexible backing 227 to the flexible barrier 213. While anadhesive is the preferred method of attachment when the flexible backing227 is surface bonded to the flexible barrier 213, any suitableattachment may be used.

The flexible barrier 213 includes a plurality of projections 231extending from the wing portions 219 on a surface of the flexiblebarrier 213. The projections 231 may be cylindrical, spherical,hemispherical, cubed, or any other shape, as long as at least someportion of each projection 231 is in a plane different than the planeassociated with the side of the flexible backing 213 to which theprojections 231 are attached. In this regard, a particular projection231 is not even required to have the same shape or size as otherprojections 231; in fact, the projections 231 may include a random mixof different shapes and sizes. Consequently, the distance by which eachprojection 231 extends from the flexible barrier 213 could vary, but mayalso be uniform among the plurality of projections 231.

The placement of projections 231 on the flexible barrier 213 creates aplurality of flow channels 233 between the projections. When theprojections 231 are of uniform shape and size and are spaced uniformlyon the flexible barrier 213, the flow channels 233 created between theprojections 231 are similarly uniform. Variations in the size, shape,and spacing of the projections 231 may be used to alter the size andflow characteristics of the flow channels 233.

A reduced-pressure delivery tube 241 is positioned within the arcuatechannel 223 and is attached to the flexible barrier 213 as illustratedin FIG. 5. The reduced-pressure delivery tube 241 may be attached solelyto the flexible barrier 213 or the flexible backing 227, or the tube 241could be attached to both the flexible barrier 213 and the flexiblebacking 227. The reduced-pressure delivery tube 241 includes a distalorifice 243 at a distal end of the tube 241. The tube 241 may bepositioned such that the distal orifice 243 is located at any pointalong the arcuate channel 223, but the tube 241 is preferably positionedsuch that the distal orifice 243 is located approximately midway alongthe longitudinal length of the arcuate channel 223. The distal orifice243 is preferably made elliptical or oval in shape by cutting the tube241 along a plane that is oriented less than ninety (90) degrees to thelongitudinal axis of the tube 241. While the orifice 243 may also beround, the elliptical shape of the orifice 243 increases fluidcommunication with the flow channels 233 formed between the projections231.

The reduced-pressure delivery tube 241 is preferably made fromparalyne-coated silicone or urethane. However, any medical-grade tubingmaterial may be used to construct the reduced-pressure delivery tube241. Other coatings that may coat the tube include heparin,anti-coagulants, anti-fibrinogens, anti-adherents, anti-thrombinogens,and hydrophilic coatings.

In one embodiment, the reduced-pressure delivery tube 241 may alsoinclude vent openings, or vent orifices 251 positioned along thereduced-pressure delivery tube 241 as either an alternative to thedistal orifice 243 or in addition to the distal orifice 243 to furtherincrease fluid communication between the reduced-pressure delivery tube241 and the flow channels 233. The reduced-pressure delivery tube 241may be positioned along only a portion of the longitudinal length of thearcuate channel 223 as shown in FIGS. 1-5, or alternatively may bepositioned along the entire longitudinal length of the arcuate channel223. If positioned such that the reduced-pressure delivery tube 241occupies the entire length of the arcuate channel 223, the distalorifice 243 may be capped such that all fluid communication between thetube 241 and the flow channels 233 occurs through the vent openings 251.

The reduced-pressure delivery tube 241 further includes a proximalorifice 255 at a proximal end of the tube 241. The proximal orifice 255is configured to mate with a reduced pressure source, which is describedin more detail below with reference to FIG. 9. The reduced-pressuredelivery tube 241 illustrated in FIGS. 1-3, 4A, and 5 includes only asingle lumen, or passageway 259. It is possible, however, for thereduced-pressure delivery tube 241 to include multiple lumens such as adual lumen tube 261 illustrated in FIG. 4B. The dual lumen tube 261includes a first lumen 263 and a second lumen 265. The use of a duallumen tube provides separate paths of fluid communication between theproximal end of the reduced-pressure delivery tube 241 and the flowchannels 233. For example, the use of the dual lumen tube 261 may beused to allow communication between the reduced pressure source and theflow channels 233 along the first lumen 263. The second lumen 265 may beused to introduce a fluid to the flow channels 233. The fluid may befiltered air or other gases, antibacterial agents, antiviral agents,cell-growth promotion agents, irrigation fluids, chemically activefluids, or any other fluid. If it is desired to introduce multiplefluids to the flow channels 233 through separate fluid communicationpaths, a reduced-pressure delivery tube may be provided with more thantwo lumens.

Referring still to FIG. 4B, a horizontal divider 271 separates the firstand second lumens 263, 265 of the reduced-pressure delivery tube 261,resulting in the first lumen 263 being positioned above the second lumen265. The relative position of the first and second lumens 263, 265 mayvary, depending on how fluid communication is provided between thelumens 263, 265 and the flow channels 233. For example, when the firstlumen 263 is positioned as illustrated in FIG. 4B, vent openings similarto vent openings 251 may be provided to allow communication with theflow channels 233. When the second lumen 263 is positioned asillustrated in FIG. 4B, the second lumen 263 may communicate with theflow channels 233 through a distal orifice similar to distal orifice243. Alternatively, the multiple lumens of a reduced-pressure deliverytube could be positioned side by side with a vertical divider separatingthe lumens, or the lumens could be arranged concentrically or coaxially.

It should be apparent to a person having ordinary skill in the art thatthe provision of independent paths of fluid communication could beaccomplished in a number of different ways, including that of providinga multi-lumen tube as described above. Alternatively, independent pathsof fluid communication may be provided by attaching a single lumen tubeto another single lumen tube, or by using separate, unattached tubeswith single or multiple lumens.

If separate tubes are used to provide separate paths of fluidcommunication to the flow channels 233, the spine portion 215 mayinclude multiple arcuate channels 223, one for each tube. Alternativelythe arcuate channel 223 may be enlarged to accommodate multiple tubes.An example of a reduced-pressure delivery apparatus having areduced-pressure delivery tube separate from a fluid delivery tube isdiscussed in more detail below with reference to FIG. 9.

Referring to FIGS. 6-8, a reduced pressure delivery apparatus, or wingmanifold 311 according to the principles of the present inventionincludes a flexible barrier 313 having a spine portion 315 and a pair ofwing portions 319. Each wing portion 319 is positioned along oppositesides of the spine portion 315. The spine portion 315 forms an arcuatechannel 323 that may or may not extend the entire length of the wingmanifold 311. Although the spine portion 315 may be centrally located onthe wing manifold 311 such that the size of the wing portions 319 isequal, the spine portion 315 may also be offset as illustrated in FIGS.6-8, resulting in one of the wing portions 319 being wider than theother wing portion 319. The extra width of one of the wing portions 319may be particularly useful if the wing manifold 311 is being used inconnection with bone regeneration or healing and the wider wing manifold311 is to be wrapped around fixation hardware attached to the bone.

A cellular material 327 is attached to the flexible barrier 313 and maybe provided as a single piece of material that covers the entire surfaceof the flexible barrier 313, extending across the spine portion 315 andboth wing portions 319. The cellular material 327 includes an attachmentsurface (not visible in FIG. 6) that is disposed adjacent to theflexible barrier 313, a main distribution surface 329 opposite theattachment surface, and a plurality of perimeter surfaces 330.

In one embodiment the flexible barrier 313 may be similar to flexiblebarrier 213 and include a flexible backing. While an adhesive is apreferred method of attaching the cellular material 327 to the flexiblebarrier 313, the flexible barrier 313 and cellular material 327 could beattached by any other suitable attachment method or left for the user toassemble at the site of treatment. The flexible barrier 313 and/orflexible backing serve as an impermeable barrier to transmission offluids such as liquids, air, and other gases.

In one embodiment, a flexible barrier and flexible backing may not beseparately provided to back the cellular material 327. Rather, thecellular material 327 may have an integral barrier layer that is animpermeable portion of the cellular material 327. The barrier layercould be formed from closed-cell material to prevent transmission offluids, thereby substituting for the flexible barrier 313. If anintegral barrier layer is used with the cellular material 327, thebarrier layer may include a spine portion and wing portions as describedpreviously with reference to the flexible barrier 313.

The flexible barrier 313 is preferably made from an elastomeric materialsuch as a silicone polymer. An example of a suitable silicone polymerincludes MED-6015 manufactured by Nusil Technologies of Carpinteria,Calif. It should be noted, however, that the flexible barrier 313 couldbe made from any other biocompatible, flexible material. If the flexiblebarrier encases or otherwise incorporates a flexible backing, theflexible backing is preferably made from a polyester knit fabric such asBard 6013 manufactured by C.R. Bard of Tempe, Ariz. However, theflexible backing 227 could be made from any biocompatible, flexiblematerial that is capable of adding strength and durability to theflexible barrier 313.

In one embodiment, the cellular material 327 is an open-cell,reticulated polyetherurethane foam with pore sizes ranging from about400-600 microns. An example of this foam may include GranuFoammanufactured by Kinetic Concepts, Inc. of San Antonio, Tex. The cellularmaterial 327 may also be gauze, felted mats, or any other biocompatiblematerial that provides fluid communication through a plurality ofchannels in three dimensions.

The cellular material 327 is primarily an “open cell” material thatincludes a plurality of cells fluidly connected to adjacent cells. Aplurality of flow channels is formed by and between the “open cells” ofthe cellular material 327. The flow channels allow fluid communicationthroughout that portion of the cellular material 327 having open cells.The cells and flow channels may be uniform in shape and size, or mayinclude patterned or random variations in shape and size. Variations inshape and size of the cells of the cellular material 327 result invariations in the flow channels, and such characteristics can be used toalter the flow characteristics of fluid through the cellular material327. The cellular material 327 may further include portions that include“closed cells.” These closed-cell portions of the cellular material 327contain a plurality of cells, the majority of which are not fluidlyconnected to adjacent cells. An example of a closed-cell portion isdescribed above as a barrier layer that may be substituted for theflexible barrier 313. Similarly, closed-cell portions could beselectively disposed in the cellular material 327 to preventtransmission of fluids through the perimeter surfaces 330 of thecellular material 327.

The flexible barrier 313 and cellular material 327 may also beconstructed from bioresorbable materials that do not have to be removedfrom a patient's body following use of the reduced pressure deliveryapparatus 311. Suitable bioresorbable materials may include, withoutlimitation, a polymeric blend of polylactic acid (PLA) and polyglycolicacid (PGA). The polymeric blend may also include without limitationpolycarbonates, polyfumarates, and capralactones. The flexible barrier313 and the cellular material 327 may further serve as a scaffold fornew cell-growth, or a scaffold material may be used in conjunction withthe flexible barrier 313, flexible backing 327, and/or cellular material327 to promote cell-growth. Suitable scaffold materials may include,without limitation, calcium phosphate, collagen, PLA/PGA, coral hydroxyapatites, carbonates, or processed allograft materials. Preferably, thescaffold material will have a high void-fraction (i.e. a high content ofair).

A reduced-pressure delivery tube 341 is positioned within the arcuatechannel 323 and is attached to the flexible barrier 313. Thereduced-pressure delivery tube 341 may also be attached to the cellularmaterial 327, or in the case of only a cellular material 327 beingpresent, the reduced-pressure delivery tube 341 may be attached to onlythe cellular material 327. The reduced-pressure delivery tube 341includes a distal orifice 343 at a distal end of the tube 341 similar tothe distal orifice 243 of FIG. 5. The reduced-pressure delivery tube 341may be positioned such that the distal orifice 343 is located at anypoint along the arcuate channel 323, but is preferably locatedapproximately midway along the longitudinal length of the arcuatechannel 323. The distal orifice 343 is preferably made elliptical oroval in shape by cutting the tube 341 along a plane that is orientedless than ninety (90) degrees to the longitudinal axis of the tube 341.While the orifice may also be round, the elliptical shape of the orificeincreases fluid communication with the flow channels in the cellularmaterial 327.

In one embodiment, the reduced-pressure delivery tube 341 may alsoinclude vent openings, or vent orifices (not shown) similar to ventopenings 251 of FIG. 5. The vent openings are positioned along the tube341 as either an alternative to the distal orifice 343 or in addition tothe distal orifice 343 to further increase fluid communication betweenthe reduced-pressure delivery tube 341 and the flow channels. Aspreviously described, the reduced-pressure delivery tube 341 may bepositioned along only a portion of the longitudinal length of thearcuate channel 323, or alternatively may be positioned along the entirelongitudinal length of the arcuate channel 323. If positioned such thatthe reduced-pressure delivery tube 341 occupies the entire arcuatechannel 323, the distal orifice 343 may be capped such that all fluidcommunication between the tube 341 and the flow channels occurs throughthe vent openings.

Preferably, the cellular material 327 overlays and directly contacts thereduced-pressure delivery tube 341. The cellular material 327 may beconnected to the reduced-pressure delivery tube 341, or the cellularmaterial 327 may simply be attached to the flexible barrier 313. If thereduced-pressure delivery tube 341 is positioned such that it onlyextends to a midpoint of the arcuate channel 323, the cellular material327 may also be connected to the spine portion 315 of the flexiblebarrier 313 in that area of the arcuate channel 323 that does notcontain the reduced-pressure delivery tube 341.

The reduced-pressure delivery tube 341 further includes a proximalorifice 355 at a proximal end of the tube 341. The proximal orifice 355is configured to mate with a reduced-pressure source, which is describedin more detail below with reference to FIG. 9. The reduced-pressuredelivery tube 341 illustrated in FIGS. 6-8 includes only a single lumen,or passageway 359. It is possible, however, for the reduced-pressuredelivery tube 341 to include multiple lumens such as those describedpreviously with reference to FIG. 4B. The use of a multiple lumen tubeprovides separate paths of fluid communication between the proximal endof the reduced-pressure delivery tube 341 and the flow channels aspreviously described. These separate paths of fluid communication mayalso be provided by separate tubes having single or multiple lumens thatcommunicate with the flow channels.

Referring to FIGS. 8A and 8B, a reduced pressure delivery apparatus 371according to the principles of the present invention includes a reducedpressure delivery tube 373 having an extension portion 375 at a distalend 377 of the reduced pressure delivery tube 373. The extension portion375 is preferably arcuately shaped to match the curvature of the reducedpressure delivery tube 373. The extension portion 375 may be formed byremoving a portion of the reduced pressure delivery tube 373 at thedistal end 377, thereby forming a cut-out 381 having a shoulder 383. Aplurality of projections 385 is disposed on an inner surface 387 of thereduced pressure delivery tube 373 to form a plurality of flow channels391 between the projections 385. The projections 385 may be similar insize, shape, and spacing as the projections described with reference toFIGS. 1-5. The reduced pressure delivery apparatus 371 is particularlysuited for applying reduced pressure to and regenerating tissue onconnective tissues that are capable of being received within the cut-out381. Ligaments, tendons, and cartilage are non-limiting examples of thetissues that may be treated by reduced pressure delivery apparatus 371.

Referring to FIG. 9, a reduced pressure delivery apparatus 411 similarto the other reduced pressure delivery apparatuses described herein isused to apply a reduced pressure tissue treatment to a tissue site 413,such as a human bone 415 of a patient. When used to promote bone tissuegrowth, reduced pressure tissue treatment can increase the rate ofhealing associated with a fracture, a non-union, a void, or other bonedefects. It is further believed that reduced pressure tissue treatmentmay be used to improve recovery from osteomyelitis. The therapy mayfurther be used to increase localized bone densities in patientssuffering from osteoporosis. Finally, reduced pressure tissue treatmentmay be used to speed and improve oseointegration of orthopedic implantssuch as hip implants, knee implants, and fixation devices.

Referring still to FIG. 9, the reduced pressure delivery apparatus 411includes a reduced-pressure delivery tube 419 having aproximal end 421fluidly connected to a reduced pressure source 427. The reduced pressuresource 427 is a pump or any other device that is capable of applying areduced pressure to the tissue site 413 through the reduced pressuredelivery tube 419 and a plurality of flow channels associated with thereduced pressure delivery apparatus 411. Applying reduced pressure tothe tissue site 413 is accomplished by placing the wing portions of thereduced pressure delivery apparatus 411 adjacent the tissue site 413,which in this particular example involves wrapping the wing portionsaround a void defect 429 in the bone 415. The reduced pressure deliveryapparatus 411 may be surgically or percutaneously inserted. Whenpercutaneously inserted, the reduced-pressure delivery tube 419 ispreferably inserted through a sterile insertion sheath that penetratesthe skin tissue of the patient.

The application of reduced pressure tissue treatment typically generatesgranulation tissue in the area surrounding the tissue site 413.Granulation tissue is a common tissue that often forms prior to tissuerepair in the body. Under normal circumstances, granulation tissue mayform in response to a foreign body or during wound healing. Granulationtissue typically serves as a scaffold for healthy replacement tissue andfurther results in the development of some scar tissue. Granulationtissue is highly vascularized, and the increased growth and growth rateof the highly vascularized tissue in the presence of reduced pressurepromotes new tissue growth at the tissue site 413.

Referring still to FIG. 9, a fluid delivery tube 431 may be fluidlyconnected at a distal end to the flow channels of the reduced pressuredelivery apparatus 411. The fluid delivery tube 431 includes a proximalend 432 that is fluidly connected to a fluid delivery source 433. If thefluid being delivered to the tissue site is air, the air is preferablyfiltered by a filter 434 capable of filtering particles at least assmall as 0.22 μm in order to clean and sterilize the air. Theintroduction of air to the tissue site 413, especially when the tissuesite 413 is located beneath the surface of the skin, is important tofacilitate good drainage of the tissue site 413, thereby reducing orpreventing obstruction of the reduced pressure delivery tube 419. Thefluid delivery tube 431 and fluid delivery source 433 could also be usedto introduce other fluids to the tissue site 413, including withoutlimitation an antibacterial agent, an antiviral agent, a cell-growthpromotion agent, an irrigation fluid, or other chemically active agents.When percutaneously inserted, the fluid delivery tube 431 is preferablyinserted through a sterile insertion sheath that penetrates the skintissue of the patient.

A pressure sensor 435 may be operably connected to the fluid deliverytube 431 to indicate whether the fluid delivery tube 431 is occludedwith blood or other bodily fluids. The pressure sensor 435 may beoperably connected to the fluid delivery source 433 to provide feedbackso that the amount of fluid introduced to the tissue site 413 iscontrolled. A check valve (not shown) may also be operably connectednear the distal end of the fluid delivery tube 431 to prevent blood orother bodily fluids from entering the fluid delivery tube 431.

The independent paths of fluid communication provided by reducedpressure delivery tube 419 and fluid delivery tube 431 may beaccomplished in a number of different ways, including that of providinga single, multi-lumen tube as described previously with reference toFIG. 4B. A person of ordinary skill in the art will recognize that thesensors, valves, and other components associated with the fluid deliverytube 431 could also be similarly associated with a particular lumen inthe reduced pressure delivery tube 419 if a multi-lumen tube is used. Itis preferred that any lumen or tube that fluidly communicates with thetissue site be coated with an anti-coagulent to prevent a build-up ofbodily fluids or blood within the lumen or tube. Other coatings that maycoat the lumens or tubes include without limitation heparin,anti-coagulants, anti-fibrinogens, anti-adherents, anti-thrombinogens,and hydrophilic coatings.

Referring to FIGS. 10-19, testing has shown the positive effects ofreduced pressure tissue treatment when applied to bone tissue. In oneparticular test, reduced pressure tissue treatment was applied to thecranium of several rabbits to determine its effect on bone growth andregeneration. The specific goals of the test were to discover the effectof reduced pressure tissue treatment on rabbits having no defect on orinjury to the cranium, the effect of reduced pressure tissue treatmenton rabbits having critical-size defects on the cranium, and the effectof using a scaffold material with reduced pressure tissue treatment totreat critical-size defects on the cranium. The specific testingprotocol and number of rabbits are listed below in Table 1.

TABLE 1 Testing Protocol No. of Rabbits Protocol 4 No defect on cranium;reduced pressure tissue treatment (RPTT) applied through cellular foam(GranuFoam) on top of intact periosteum for 6 days followed by immediatetissue harvest 4 No defect on cranium; cellular foam (GranuFoam) placedon top of intact periosteum without RPTT (control) for 6 days followedby immediate tissue harvest 4 One critical-size defect withstainless-steel screen placed on defect; one critical-size defect withcalcium phosphate scaffold placed in defect; 24 hours RPTT applied toboth defects; tissue harvest 2 weeks post-surgery 4 One critical-sizedefect with stainless-steel screen placed on defect; one critical-sizedefect with calcium phosphate scaffold placed in defect; 24 hours RPTTapplied to both defects; tissue harvest 12 weeks post-surgery 4 Onecritical-size defect with stainless-steel screen placed on defect; onecritical-size defect with calcium phosphate scaffold placed in defect; 6days RPTT applied to both defects; tissue harvest 2 weeks post-surgery 4One critical-size defect with stainless-steel screen placed on defect;one critical-size defect with calcium phosphate scaffold placed indefect; 6 days RPTT applied to both defects; tissue harvest 12 weekspost-surgery 4 One critical-size defect with stainless-steel screenplaced on defect; one critical-size defect with calcium phosphatescaffold placed in defect; no RPTT applied (control); tissue harvest 2weeks post-surgery 4 One critical-size defect with stainless-steelscreen placed on defect; one critical-size defect with calcium phosphatescaffold placed in defect; no RPTT applied (control); tissue harvest 12weeks post-surgery 4 Native control (no surgery; no RPTT) 4 Sham surgery(no defects, no RPTT); tissue harvest 6 days post-surgery

Critical-size defects are defects in a tissue (e.g. the cranium), thesize of which is large enough that the defect will not heal solely byin-life recovery. For rabbits, boring a full-thickness hole through thecranium that is approximately 15 mm in diameter creates a critical-sizedefect of the cranium.

Referring more specifically to FIG. 10, a histological section of arabbit cranium having naïve, undamaged bone is illustrated. The bonetissue of the cranium is colored magenta, the surrounding soft tissuewhite, and the layer of periosteum is highlighted by yellow asterisks.In FIG. 11, the rabbit cranium is illustrated following the applicationof reduced pressure tissue treatment for 6 days followed by immediatetissue harvest. The bone and periosteum are visible, and a layer ofgranulation tissue has developed. In FIG. 12, the rabbit cranium isillustrated following the application of reduced pressure tissuetreatment for 6 days and followed by immediate tissue harvest. Thehistological section of FIG. 12 is characterized by the development ofnew bone tissue underlying the granulation tissue. The bone tissue ishighlighted by yellow asterisks. In FIG. 13, the rabbit cranium isillustrated following the application of reduced pressure tissuetreatment for 6 days followed by immediate tissue harvest. The new boneand periosteum are visible. This histological appearance of bone tissuedevelopment in response to reduced pressure tissue treatment is verysimilar to the histological appearance of bone development in a veryyoung animal that is undergoing very rapid growth and deposition of newbone.

Referring more specifically to FIGS. 14-19, several photographs andhistological sections are illustrated showing the procedures and resultsof reduced pressure tissue treatment on a rabbit cranium havingcritical-size defects. In FIG. 14, a rabbit cranium is illustrated onwhich two critical-size defects have been created. The full-thicknesscritical-size defects are approximately 15 mm in diameter. In FIG. 15, astainless-steel screen has been placed over one of the critical-sizedefects, and a calcium phosphate scaffold has been placed within thesecond critical-size defect. In FIG. 16, a reduced pressure tissuetreatment apparatus similar to those described herein is used to applyreduced pressure to the critical-size defects. The amount of pressureapplied to each defect was −125 mm Hg gauge pressure. The reducedpressure was applied according to one of the protocols listed inTable 1. In FIG. 17, a histological section of cranium following six-dayreduced pressure tissue treatment and twelve week post-surgery harvestis illustrated. The section illustrated includes calcium phosphatescaffold, which is indicated by red arrows. The application of reducedpressure tissue treatment resulted in the significant growth of new bonetissue, which is highlighted in FIG. 17 by yellow asterisks. The amountof bone growth is significantly greater than in critical-size defectscontaining identical calcium phosphate scaffolds but which were nottreated with reduced pressure tissue treatment. This observationsuggests there may be a threshold level or duration of therapy requiredto elicit a prolific new-bone response. Effects of reduced pressuretissue treatment are most pronounced in the specimens collected 12 weekspost-surgery, indicating the reduced pressure tissue treatment initiatesa cascade of biological events leading to enhanced formation of new bonetissue.

Critical-size defects covered with stainless steel screens (FIG. 15) butwithout scaffold material in the defect served as intra-animal controlswith minimal new-bone growth. These data highlight the advantage of anappropriate scaffold material and the positive effect of reducedpressure tissue treatment on scaffold integration and biologicalperformance. In FIGS. 18 and 19, radiographs of scaffold-filled,critical-size defects are illustrated following six days of reducedpressure tissue treatment. FIG. 18 illustrates the defect two weekspost-surgery and indicates some new bone deposition within the scaffold.The primary structure of the scaffold is still evident. FIG. 19illustrates the defect twelve weeks post surgery and shows almostcomplete healing of the critical-size defect and a near complete loss ofthe primary scaffold architecture due to tissue integration, i.e. newbone formation within the scaffold matrix.

Referring to FIG. 20, a reduced pressure delivery system 711 accordingto an embodiment of the present invention delivers reduced pressuretissue treatment to a tissue site 713 of a patient. The reduced pressuredelivery system 711 includes a manifold delivery tube 721. The manifolddelivery tube 721 may be a catheter or cannula and may include featuressuch as a steering unit 725 and a guide wire 727 that allow the manifolddelivery tube 721 to be guided to the tissue site 713. Placement anddirection of the guide wire 727 and the manifold delivery tube 721 maybe accomplished by using endoscopy, ultrasound, fluoroscopy,auscultation, palpation, or any other suitable localization technique.The manifold delivery tube 721 is provided to percutaneously insert areduced pressure delivery apparatus to the tissue site 713 of thepatient. When percutaneously inserted, the manifold delivery tube 721 ispreferably inserted through a sterile insertion sheath that penetratesthe skin tissue of the patient.

In FIG. 20, the tissue site 713 includes bone tissue adjacent a fracture731 on a bone 733 of the patient. The manifold delivery tube 721 isinserted through the patient's skin 735 and any soft tissue 739surrounding the bone 733. As previously discussed, the tissue site 713may also include any other type of tissue, including without limitationadipose tissue, muscle tissue, neural tissue, dermal tissue, vasculartissue, connective tissue, cartilage, tendons, or ligaments.

Referring to FIGS. 21 and 22, the reduced pressure delivery system 711is further illustrated. The manifold delivery tube 721 may include atapered distal end 743 to ease insertion through the patient's skin 735and soft tissue 739. The tapered distal end 743 may further beconfigured to flex radially outward to an open position such that theinner diameter of the distal end 743 would be substantially the same asor greater than the inner diameter at other portions of the tube 721.The open position of the distal end 743 is schematically illustrated inFIG. 21 by broken lines 737.

The manifold delivery tube 721 further includes a passageway 751 inwhich a reduced pressure delivery apparatus 761, or any other reducedpressure delivery apparatus, is contained. The reduced pressure deliveryapparatus 761 includes a flexible barrier 765 and/or cellular material767 similar to that described with reference to FIGS. 6-8. The flexiblebarrier 765 and/or cellular material 767 is preferably rolled, folded,or otherwise compressed around a reduced pressure delivery tube 769 toreduce the cross-sectional area of the reduced pressure deliveryapparatus 761 within the passageway 751.

The reduced pressure delivery apparatus 761 may be placed within thepassageway 751 and guided to the tissue site 713 following the placementof the distal end 743 manifold delivery tube 721 at the tissue site 713.Alternatively, the reduced pressure delivery apparatus 761 may bepre-positioned within the passageway 751 prior to the manifold deliverytube 721 being inserted into the patient. If the reduced pressuredelivery apparatus 761 is to be pushed through the passageway 751, abiocompatible lubricant may be used to reduce friction between thereduced pressure delivery apparatus 761 and the manifold delivery tube721. When the distal end 743 has been positioned at the tissue site 713and the reduced pressure delivery apparatus 761 has been delivered tothe distal end 743, the reduced pressure delivery apparatus 761 is thenpushed toward the distal end 743, causing the distal end 743 to expandradially outward into the open position. The reduced pressure deliveryapparatus 761 is pushed out of the manifold delivery tube 721,preferably into a void or space adjacent the tissue site 713. The voidor space is typically formed by dissection of soft tissue, which may beaccomplished by percutaneous means. In some cases, the tissue site 713may be located at a wound site, and a void may be naturally present dueto the anatomy of the wound. In other instances, the void may be createdby balloon dissection, sharp dissection, blunt dissection,hydrodissection, pneumatic dissection, ultrasonic dissection,electrocautery dissection, laser dissection, or any other suitabledissection technique. When the reduced pressure delivery apparatus 761enters the void adjacent the tissue site 713, the flexible barrier 765and/or cellular material 767 of the reduced pressure delivery apparatus761 either unrolls, unfolds, or decompresses (see FIG. 22) such that thereduced pressure delivery apparatus 761 can be placed in contact withthe tissue site 713. Although not required, the flexible barrier 765and/or cellular material 767 may be subjected to a vacuum or reducedpressure supplied through the reduced pressure delivery tube 769 tocompress the flexible barrier 765 and/or cellular material 767. Theunfolding of the flexible barrier 765 and/or cellular material 767 maybe accomplished by either relaxing the reduced pressure supplied throughthe reduced pressure delivery tube 769 or by supplying a positivepressure through the reduced pressure delivery tube 769 to assist theunrolling process. Final placement and manipulation of the reducedpressure delivery apparatus 761 may be accomplished by using endoscopy,ultrasound, fluoroscopy, auscultation, palpation, or any other suitablelocalization technique. Following placement of the reduced pressuredelivery apparatus 761, the manifold delivery tube 721 is preferablyremoved from the patient, but the reduced pressure delivery tubeassociated with reduced pressure delivery apparatus 761 remains in situto allow percutaneous application of reduced pressure to the tissue site713.

Referring to FIGS. 23-25, a reduced pressure delivery system 811according to an embodiment of the present invention includes a manifolddelivery tube 821 having a tapered distal end 843 that is configured toflex radially outward to an open position such that the inner diameterof the distal end 843 would be substantially the same as or greater thanthe inner diameter at other portions of the tube 821. The open positionof the distal end 843 is schematically illustrated in FIGS. 23-25 bybroken lines 837.

The manifold delivery tube 821 further includes a passageway in which areduced pressure delivery apparatus 861 similar to the other reducedpressure delivery apparatuses described herein is contained. The reducedpressure delivery apparatus 861 includes a flexible barrier 865 and/or acellular material 867 that is preferably rolled, folded, or otherwisecompressed around a reduced pressure delivery tube 869 to reduce thecross-sectional area of the reduced pressure delivery apparatus 861within the passageway.

An impermeable membrane 871 having an inner space 873 is disposed aroundthe reduced pressure delivery apparatus 861 such that the reducedpressure delivery apparatus 861 is contained within the inner space 873of the impermeable membrane 871. The impermeable membrane 871 may be aballoon, a sheath, or any other type of membrane that is capable ofpreventing fluid transmission such that the impermeable membrane 871 canassume at least one of a compressed position (see FIG. 23), a relaxedposition (see FIG. 24), and an expanded position (see FIGS. 25 and 25A).The impermeable membrane 871 may be sealingly connected to the manifolddelivery tube 821 such that the inner space 873 of the impermeablemembrane 871 is in fluid communication with the passageway of themanifold delivery tube 821, The impermeable membrane 871 mayalternatively be attached to the reduced pressure delivery tube 869 suchthat the inner space 873 of the impermeable membrane 871 is in fluidcommunication with the passageway of the reduced pressure delivery tube869. The impermeable membrane 871 instead may be attached to a separatecontrol tube or control lumen (see for example FIG. 25A) that fluidlycommunicates with the inner space 873.

In one embodiment, the impermeable membrane 871 may be provided tofurther reduce the cross-sectional area of the reduced pressure deliveryapparatus 861 within the passageway. To accomplish this, a pressure isapplied to the inner space 873 of the impermeable membrane 871 that isless than the ambient pressure surrounding the impermeable membrane 871.A significant portion of the air or other fluid within the inner space873 is thereby evacuated, placing the impermeable membrane 871 in thecompressed position illustrated in FIG. 23. In the compressed position,the impermeable membrane 871 is drawn inward such that a compressiveforce is applied to the reduced pressure delivery apparatus 861 tofurther reduce the cross-sectional area of the reduced pressure deliveryapparatus 861. As previously described with reference to FIGS. 21 and22, the reduced pressure delivery apparatus 861 may be delivered to thetissue site following the placement of the distal end 843 of themanifold delivery tube 821 at the tissue site. Placement andmanipulation of the impermeable membrane 871 and the reduced pressuredelivery apparatus 861 may be accomplished by using endoscopy,ultrasound, fluoroscopy, auscultation, palpation, or any other suitablelocalization technique. The impermeable membrane 871 may includeradio-opaque markers 881 that improve visualization of the impermeablemembrane 871 under fluoroscopy prior to its removal.

After pushing the reduced pressure delivery apparatus 861 through thedistal end 843, the reduced pressure applied to the inner space 873 maybe eased to place the impermeable membrane 871 in the relaxed position(see FIG. 24), thereby facilitating easier removal of the reducedpressure delivery apparatus 861 from the impermeable membrane 871. Aremoval instrument 885 such as a trocar, stylet, or other sharpinstrument may be provided to rupture the impermeable membrane 871.Preferably, the removal instrument 885 is inserted through the reducedpressure delivery tube 869 and is capable of being advanced into contactwith the impermeable membrane 871. After rupture of the impermeablemembrane 871, the removal instrument 885 and the impermeable membrane871 may be withdrawn through the manifold delivery tube 821, allowingthe flexible barrier 865 and/or cellular material 867 of the reducedpressure delivery apparatus 861 to unroll, unfold, or decompress suchthat the reduced pressure delivery apparatus 861 can be placed incontact with the tissue site. The unrolling of the flexible barrier 865and/or cellular material 867 may occur automatically following therelaxation of reduced pressure to the inner space 873 and the removal ofthe impermeable membrane 871. In some cases, a positive pressure may bedelivered through the reduced pressure delivery tube 869 to assist inunrolling or decompressing the flexible barrier 865 and/or cellularmaterial 867. Following final placement of the reduced pressure deliveryapparatus 861, the manifold delivery tube 821 is preferably removed fromthe patient, but the reduced pressure delivery tube 869 associated withthe reduced pressure delivery apparatus 861 remains in situ to allowpercutaneous application of reduced pressure to the tissue site.

The impermeable membrane 871 may also be used to dissect tissue adjacentthe tissue site prior to placing the reduced pressure delivery apparatus861 against the tissue site. After pushing the reduced pressure deliveryapparatus 861 and intact impermeable membrane 871 through the distal end843 of the manifold delivery tube 821, air or another fluid may beinjected or pumped into the inner space 873 of the impermeable membrane871. A liquid is preferably used to inflate the impermeable membrane 871since the incompressibility of liquids allow the impermeable membrane871 to expand more evenly and consistently. The impermeable membrane 871may expand radially as illustrated in FIG. 25 or directionally dependingon its method of manufacture and attachment to the manifold deliverytube 821. As the impermeable membrane 871 expands outward into theexpanded position (see FIG. 25) due to the pressure of the air or fluid,a void is dissected adjacent the tissue site. When the void is largeenough, the liquid, air or other fluid may be released from the innerspace 873 to allow the impermeable membrane 871 to assume the relaxedposition. The impermeable membrane 871 may then be ruptured aspreviously explained and the reduced pressure delivery apparatus 861inserted adjacent the tissue site.

Referring to FIG. 25A, if the impermeable membrane 871 is used primarilyto dissect tissue adjacent the tissue site, the impermeable membrane 871may be sealingly attached to the manifold delivery tube 821 such thatthe inner space 873 fluidly communicates with a secondary lumen or tube891 associated with or attached to the manifold delivery tube 821. Thesecondary lumen 891 may be used to deliver a liquid, air, or other fluidto the inner space 873 to place the impermeable membrane 871 in theexpanded position. Following dissection, the impermeable membrane 871may be relaxed and ruptured as previously described with reference toFIG. 24.

Referring to FIG. 26, a reduced pressure delivery system 911 accordingto an embodiment of the present invention includes a manifold deliverytube 921 having a tapered distal end 943 that is configured to flexradially outward to an open position such that the inner diameter of thedistal end 943 would be substantially the same as or greater than theinner diameter at other portions of the tube 921. The open position ofthe distal end 943 is schematically illustrated in FIG. 26 by brokenlines 937.

The manifold delivery tube 921 further includes a passageway in which areduced pressure delivery apparatus 961 similar to the other reducedpressure delivery apparatuses described herein is contained. The reducedpressure delivery apparatus 961 includes a flexible barrier 965 and/or acellular material 967 that is preferably rolled, folded, or otherwisecompressed around a reduced pressure delivery tube 969 to reduce thecross-sectional area of the reduced pressure delivery apparatus 961within the passageway of the manifold delivery tube 921.

An impermeable membrane 971 having an inner space 973 is disposed aroundthe reduced pressure delivery apparatus 961 such that the reducedpressure delivery apparatus 961 is contained within the inner space 973of the impermeable membrane 971. The impermeable membrane 971 includes aglue seal 977 on one end of the impermeable membrane 971 to provide analternative method of removing the reduced pressure delivery apparatus961 from the impermeable membrane 971. The impermeable membrane 971 maybe sealingly connected at another end to the manifold delivery tube 921such that the inner space 973 of the impermeable membrane 971 is influid communication with the passageway of the manifold delivery tube921. Alternatively, the impermeable membrane 971 may be attached to aseparate control tube (not shown) that fluidly communicates with theinner space 973.

Similar to the impermeable membrane 871 of FIG. 23, impermeable membrane971 may be capable of preventing fluid transmission such that theimpermeable membrane 971 can assume at least one of a compressedposition, a relaxed position, and an expanded position. Since theprocedures for placing the impermeable membrane 971 in a compressedposition and an expanded position are similar to those for impermeablemembrane 871, only the differing process of removing the reducedpressure delivery apparatus 961 is described.

The reduced pressure delivery apparatus 961 is delivered to the tissuesite within the impermeable membrane 971 and then properly positionedusing endoscopy, ultrasound, fluoroscopy, auscultation, palpation, orany other suitable localization technique. The impermeable membrane 971may include radio-opaque markers 981 that improve visualization of theimpermeable membrane 971 under fluoroscopy prior to its removal. Thereduced pressure delivery apparatus 961 is then pushed through thedistal end 943 of the manifold delivery tube 921. The reduced pressureapplied to the inner space 973 may be eased to place the impermeablemembrane 971 in the relaxed position. The reduced pressure deliveryapparatus 961 is then pushed through the glue seal 977 to exit theimpermeable membrane 971.

Referring to FIG. 26A, a reduced pressure delivery system 985 accordingto an embodiment of the present invention may not include a manifolddelivery tube similar to manifold delivery tube 921 of FIG. 26. Instead,the reduced pressure delivery system 985 may include a guide wire 987, areduced pressure delivery tube 989, and a reduced pressure deliveryapparatus 991. The reduced pressure delivery apparatus 991 includes aplurality flow channels that is fluidly connected to the reducedpressure delivery tube 989. Instead of using an independent manifolddelivery tube to deliver the reduced pressure delivery apparatus 991,the reduced pressure delivery apparatus 991 and reduced pressuredelivery tube 989 are placed on the guide wire 987, which ispercutaneously guided to a tissue site 993. Preferably, the guide wire987 and reduced pressure delivery tube 989 penetrate the skin of thepatient through a sterile sheath. By guiding the reduced pressuredelivery tube 989 and reduced pressure delivery apparatus 991 along theguide wire 987, the reduced pressure delivery apparatus 991 may beplaced at the tissue site 993 to allow percutaneous application ofreduced pressure tissue treatment.

Since the reduced pressure delivery apparatus 991 is not constrainedwithin a manifold delivery tube during delivery to the tissue site 993,it is preferable to hold the reduced pressure delivery apparatus 991 ina compressed position during delivery. If an elastic foam is used as thereduced pressure delivery apparatus 991, a biocompatible, solubleadhesive may be applied to the foam and the foam compressed. Uponarrival at the tissue site, bodily fluids or other fluids deliveredthrough the reduced pressure delivery tube 989 dissolve the adhesive,allowing the foam to expand into contact with the tissue site.Alternatively, the reduced pressure delivery apparatus 991 may be formedfrom a compressed, dry hydrogel. The hydrogel absorbs moisture followingdelivery to the tissue site 993 allowing expansion of the reducedpressure delivery apparatus 991. Still another reduced pressure deliveryapparatus 991 may be made from a thermoactive material (e.g.polyethylene glycol) that expands at the tissue site 993 when exposed tothe body heat of the patient. In still another embodiment, a compressedreduced pressure delivery apparatus 991 may be delivered to the tissuesite 993 in a dissolvable membrane.

Referring to FIG. 27, a reduced pressure delivery system 1011 accordingto an embodiment of the present invention includes a manifold deliverytube 1021 having a distal end 1043 that is inserted through a tissue ofa patient to access a tissue site 1025. The tissue site 1025 may includea void 1029 that is associated with a wound or other defect, oralternatively a void may be created by dissection, including thedissection techniques described herein.

Following placement of the distal end 1043 within the void 1029 adjacentthe tissue site 1025, an injectable, pourable, or flowable reducedpressure delivery apparatus 1035 is delivered through the manifolddelivery tube 1021 to the tissue site 1025. The reduced pressuredelivery apparatus 1035 preferably exists in a flowable state duringdelivery to the tissue site, and then, after arrival forms a pluralityof flow channels for distribution of reduced pressure or fluids. In somecases, the flowable material may harden into a solid state after arrivalat the tissue site, either through a drying process, a curing process,or other chemical or physical reaction. In other cases, the flowablematerial may form a foam in-situ following delivery to the tissue site.Still other materials may exist in a gel-like state at the tissue site1025 but still have a plurality of flow channels for delivering reducedpressure. The amount of reduced pressure delivery apparatus 1035delivered to the tissue site 1025 may be enough to partially orcompletely fill the void 1029. The reduced pressure delivery apparatus1035 may include aspects of both a manifold and a scaffold. As amanifold, the reduced pressure delivery apparatus 1035 includes aplurality of pores or open cells that may be formed in the materialafter delivery to the void 1029. The pores or open cells communicatewith one another, thereby creating a plurality of flow channels. Theflow channels are used to apply and distribute reduced pressure to thetissue site 1025. As a scaffold, the reduced pressure delivery apparatus1035 is bioresorbable and serves as a substrate upon and within whichnew tissue may grow.

In one embodiment, the reduced pressure delivery apparatus 1035 mayinclude poragens such as NaCl or other salts that are distributedthroughout a liquid or viscous gel. After the liquid or viscous gel isdelivered to the tissue site 1025, the material conforms to the void1029 and then cures into a solid mass. The water-soluble NaCl poragensdissolve in the presence of bodily fluids leaving a structure withinterconnected pores, or flow channels. Reduced pressure and/or fluid isdelivered to the flow channels. As new tissue develops, the tissue growsinto the pores of the reduced pressure delivery apparatus 1035, and thenultimately replaces the reduced pressure delivery apparatus 1035 as itdegrades. In this particular example, the reduced pressure deliveryapparatus 1035 serves not only as a manifold, but also as a scaffold fornew tissue growth.

In another embodiment, the reduced pressure delivery apparatus 1035 isan alginate mixed with 400 μM mannose beads. The poragens or beads maybe dissolved by local body fluids or by irrigational or other fluidsdelivered to the reduced pressure delivery apparatus 1035 at the tissuesite. Following dissolution of the poragens or beads, the spacespreviously occupied by the poragens or beads become voids that areinterconnected with other voids to form the flow channels within thereduced pressure delivery apparatus 1035.

The use of poragens to create flow channels in a material is effective,but it also forms pores and flow channels that are limited in size toapproximately the particle size of the selected poragen. Instead ofporagens, a chemical reaction may be used to create larger pores due tothe formation of gaseous by-products. For example, in one embodiment, aflowable material may be delivered to the tissue site 1025 that containssodium bicarbonate and citric acid particles (non-stoichiometric amountsmay be used). As the flowable material forms a foam or solid in-situ,bodily fluids will initiate an acid-base reaction between the sodiumbicarbonate and the citric acid. The resulting carbon dioxide gasparticles that are produced create larger pore and flow channelsthroughout the reduced pressure delivery apparatus 1035 than techniquesrelying on poragen dissolution.

The transformation of the reduced pressure delivery apparatus 1035 froma liquid or viscous gel into a solid or a foam can be triggered by pH,temperature, light, or a reaction with bodily fluids, chemicals or othersubstances delivered to the tissue site. The transformation may alsooccur by mixing multiple reactive components. In one embodiment, thereduced pressure delivery apparatus 1035 is prepared by selectingbioresorbable microspheres made from any bioresorbable polymer. Themicrospheres are dispersed in a solution containing a photoinitiator anda hydrogel-forming material such as hyaluronic acid, collagen, orpolyethylene glycol with photoreactive groups. The microsphere-gelmixture is exposed to light for a brief period of time to partiallycrosslink the hydrogel and immobilize the hydrogel on the microspheres.The excess solution is drained, and the microspheres are then dried. Themicrospheres are delivered to the tissue site by injection or pouring,and following delivery, the mixture absorbs moisture, and the hydrogelcoating becomes hydrated. The mixture is then again exposed to light,which crosslinks the microspheres, creating a plurality of flowchannels. The crosslinked microspheres then serve as a manifold todeliver reduced pressure to the tissue site and as a porous scaffold topromote new tissue growth.

In addition to the preceding embodiments described herein, the reducedpressure delivery apparatus 1035 may be made from a variety ofmaterials, including without limitation calcium phosphate, collagen,alginate, cellulose, or any other equivalent material that is capable ofbeing delivered to the tissue site as a gas, liquid, gel, paste, putty,slurry, suspension, or other flowable material and is capable of formingmultiple flow paths in fluid communication with the tissue site. Theflowable material may further include particulate solids, such as beads,that are capable of flowing through the manifold delivery tube 1021 ifthe particulate solids are sufficiently small in size. Materials thatare delivered to the tissue site in a flowable state may polymerize orgel in-situ.

As previously described, the reduced pressure delivery apparatus 1035may injected or poured directly into the void 1029 adjacent the tissuesite 1025. Referring to FIG. 27A, the manifold delivery tube 1021 mayinclude an impermeable or semi-permeable membrane 1051 at the distal end1043 of the manifold delivery tube 1021. The membrane 1051 includes aninner space 1055 that fluidly communicates with a secondary lumen 1057attached to the manifold delivery tube 1021. The manifold delivery tube1021 is guided to the tissue site 1025 over a guide wire 1061.

The reduced pressure delivery apparatus 1035 may be injected or pouredthrough the secondary lumen 1057 to fill the inner space 1055 of themembrane 1051. As the fluid or gel fills the membrane 1051, the membrane1051 expands to fill the void 1029 such that the membrane is in contactwith the tissue site 1025. As the membrane 1051 expands, the membrane1051 may be used to dissect additional tissue adjacent or near thetissue site 1025. The membrane 1051, if impermeable, may be physicallyruptured and removed, leaving behind the reduced pressure deliveryapparatus 1035 in contact with the tissue site 1025. Alternatively, themembrane 1051 may be made from a dissolvable material that dissolves inthe presence of bodily fluids or biocompatible solvents that may bedelivered to the membrane 1051. If the membrane 1051 is semi-permeable,the membrane 1051 may remain in situ. The semi-permeable membrane 1051allows communication of reduced pressure and possibly other fluids tothe tissue site 1025.

Referring to FIG. 28, a method 1111 of administering a reduced pressuretissue treatment to a tissue site includes at 1115 surgically insertinga manifold adjacent the tissue site, the manifold having a plurality ofprojections extending from a flexible barrier to create a plurality offlow channels between the projections. The manifold is positioned at1119 such that at least a portion of the projections are in contact withthe tissue site. At 1123, a reduced pressure is applied through themanifold to the tissue site.

Referring to FIG. 29, a method 1211 of administering a reduced pressuretissue treatment to a tissue site includes at 1215 percutaneouslyinserting a manifold adjacent the tissue site. The manifold may includea plurality of projections extending from a flexible barrier to create aplurality of flow channels between the projections. Alternatively, themanifold may include cellular material having a plurality of flowchannels within the cellular material. Alternatively, the manifold maybe formed from an injectable or pourable material that is delivered tothe tissue site and forms a plurality of flow channels after arriving atthe tissue site. At 1219, the manifold is positioned such that at aleast a portion of the flow channels are in fluid communication with thetissue site. A reduced pressure is applied to the tissue site throughthe manifold at 1223.

Referring to FIG. 30, a method 1311 of administering a reduced pressuretissue treatment to a tissue site includes at 1315 percutaneouslyinserting a tube having a passageway through a tissue of a patient toplace a distal end of the tube adjacent the tissue site. At 1319, aballoon associated with the tube may be inflated to dissect tissueadjacent the tissue site, thereby creating a void. At 1323, a manifoldis delivered through the passageway. The manifold may include aplurality of projections extending from a flexible barrier to create aplurality of flow channels between the projections. Alternatively, themanifold may include cellular material having a plurality of flowchannels within the cellular material. Alternatively, the manifold maybe formed from an injectable or pourable material that is delivered tothe tissue site as described previously with reference to FIG. 27. Themanifold is positioned in the void at 1327 such that at least a portionof the flow channels are in fluid communication with the tissue site. At1331, a reduced pressure is applied to the tissue site through themanifold via a reduced pressure delivery tube or any other deliverymeans.

Referring to FIG. 31, a method 1411 of administering a reduced pressuretissue treatment to a tissue site includes at 1415 percutaneouslyinserting a tube having a passageway through a tissue of a patient toplace a distal end of the tube adjacent the tissue site. At 1423, amanifold is delivered through the passageway to the tissue site withinan impermeable sheath, the impermeable sheath at 1419 having beensubjected to a first reduced pressure less than an ambient pressure ofthe sheath. At 1427, the sheath is ruptured to place the manifold incontact with the tissue site. At 1431, a second reduced pressure isapplied through the manifold to the tissue site.

Referring to FIGS. 32 and 33, a reduced pressure delivery apparatus 1511according to an embodiment of the present invention includes anorthopedic hip prosthesis 1515 for replacing the existing femoral headof a femur 1517 of a patient. The hip prosthesis 1515 includes a stemportion 1521 and a head portion 1525. The stem portion 1521 is elongatedfor insertion within a passage 1529 reamed in a shaft of the femur 1517.A porous coating 1535 is disposed around the stem portion and preferablyis constructed from sintered or vitrified ceramics or metal.Alternatively, a cellular material having porous characteristic could bedisposed around the stem portion. A plurality of flow channels 1541 isdisposed within the stem portion 1521 of the hip prosthesis 1515 suchthat the flow channels 1541 are in fluid communication with the porouscoating 1535. A connection port 1545 is fluidly connected to the flowchannels 1541, the port being configured for releasable connection to areduced pressure delivery tube 1551 and a reduced pressure deliverysource 1553. The flow channels 1541 are used to deliver a reducedpressure to the porous coating 1535 and/or the bone surrounding the hipprosthesis 1515 following implantation. The flow channels 1541 mayinclude a main feeder line 1543 that fluidly communicates with severallateral branch lines 1547, which communicate with the porous coating1535. The lateral branch lines 1545 may be oriented normal to the mainfeeder line 1543 as illustrated in FIG. 32, or may be oriented at anglesto the main feeder line 1543. An alternative method for distributing thereduced pressure includes providing a hollow hip prosthesis, and fillingthe inner space of the prosthesis with a cellular (preferably open-cell)material that is capable of fluidly communicating with the porouscoating 1535.

Referring more specifically to FIG. 33, hip prosthesis 1515 may furtherinclude a second plurality of flow channels 1561 within the stem portion1521 to provide a fluid to the porous coating 1535 and/or the bonesurrounding the hip prosthesis 1515. The fluid could include filteredair or other gases, antibacterial agents, antiviral agents, cell-growthpromotion agents, irrigation fluids, chemically active fluids, or anyother fluid. If it is desired to introduce multiple fluids to the bonesurrounding the hip prosthesis 1515, additional paths of fluidcommunication may be provided. A connection port 1565 is fluidlyconnected to the flow channels 1561, the port 1565 being configured forreleasable connection to a fluid delivery tube 1571 and a fluid deliverysource 1573. The flow channels 1561 may include a main feeder line 1583that fluidly communicates with several lateral branch lines 1585, whichcommunicate with the porous coating 1535. The lateral branch lines 1585may be oriented normal to the main feeder line 1583 as illustrated inFIG. 33, or may be oriented at angles to the main feeder line 1583.

The delivery of reduced pressure to the first plurality of flow channels1541 and the delivery of the fluid to the second plurality of flowchannels 1561 may be accomplished by separate tubes such as reducedpressure delivery tube 1551 and fluid delivery tube 1571. Alternatively,a tube having multiple lumens as described previously herein may be usedto separate the communication paths for delivering the reduced pressureand the fluid. It should further be noted that while it is preferred toprovide separate paths of fluid communication within the hip prosthesis1515, the first plurality of flow channels 1541 could be used to deliverboth the reduced pressure and the fluid to the bone surrounding the hipprosthesis 1515.

As previously described, application of reduced pressure to bone tissuepromotes and speeds the growth of new bone tissue. By using the hipprosthesis 1515 as a manifold to deliver reduced pressure to the area ofbone surrounding the hip prosthesis, recovery of the femur 1517 isfaster, and the hip prosthesis 1515 integrates more successfully withthe bone. Providing the second plurality of flow channels 1561 to ventthe bone surrounding the hip prosthesis 1515 improves the successfulgeneration of new bone around the prosthesis.

Following the application of reduced pressure through the hip prosthesis1515 for a selected amount of time, the reduced pressure delivery tube1551 and fluid delivery tube 1571 may be disconnected from theconnection ports 1545, 1565 and removed from the patient's body,preferably without a surgically-invasive procedure. The connectionbetween the connection ports 1545, 1565 and the tubes 1551, 1571 may bea manually-releasable connection that is effectuated by applying anaxially-oriented tensile force to the tubes 1551, 1571 on the outside ofthe patient's body. Alternatively, the connection ports 1545, 1565 maybe bioresorbable or dissolvable in the presence of selected fluids orchemicals such that release of the tubes 1551, 1571 may be obtained byexposing the connection ports 1545, 1565 to the fluid or chemical. Thetubes 1551, 1571 may also be made from a bioresorbable material thatdissolves over a period of time or an activated material that dissolvesin the presence of a particular chemical or other substance.

The reduced pressure delivery source 1553 may be provided outside thepatient's body and connected to the reduced pressure delivery tube 1551to deliver reduced pressure to the hip prosthesis 1515. Alternatively,the reduced pressure delivery source 1553 may be implanted within thepatient's body, either on-board or near the hip prosthesis 1515.Placement of the reduced pressure delivery source 1553 within thepatient's body eliminates the need for a percutaneous fluid connection.The implanted reduced pressure delivery source 1553 may be a traditionalpump that is operably connected to the flow channels 1541. The pump maybe powered by a battery that is implanted within the patient, or may bepowered by an external battery that is electrically and percutaneouslyconnected to the pump. The pump may also be driven directly by achemical reaction that delivers a reduced pressure and circulates fluidsthrough the flow channels 1541, 1561.

While only the stem portion 1521 and head portion 1525 of the hipprosthesis 1515 are illustrated in FIGS. 32 and 33, it should be notedthat the flow channels and means for applying reduced pressure tissuetreatment described herein could be applied to any component of the hipprosthesis 1515 that contacts bone or other tissue, including forexample the acetabular cup.

Referring to FIG. 34, a method 1611 for repairing a joint of a patientincludes at 1615 implanting a prosthesis within a bone adjacent thejoint. The prosthesis could be a hip prosthesis as described above orany other prosthesis that assists in restoring mobility to the joint ofthe patient. The prosthesis includes a plurality of flow channelsconfigured to fluidly communicate with the bone. At 1619, a reducedpressure is applied to the bone through the plurality of flow channelsto improve oseointegration of the prosthesis.

Referring to FIGS. 35 and 36, a reduced pressure delivery apparatus 1711according to an embodiment of the present invention includes anorthopedic fixation device 1715 for securing a bone 1717 of a patientthat includes a fracture 1719 or other defect. The orthopedic fixationdevice 1715 illustrated in FIGS. 35 and 36 is a plate having a pluralityof passages 1721 for anchoring the orthopedic fixation device 1715 tothe bone 1717 with screws 1725, pins, bolts, or other fasteners. Aporous coating 1735 may be disposed on a surface of the orthopedicfixation device 1715 that is to contact the bone 1717. The porouscoating is preferably constructed from sintered or vitrified ceramics ormetal. Alternatively, a cellular material having porous characteristiccould be disposed between the bone 1717 and the orthopedic fixationdevice 1715. A plurality of flow channels 1741 is disposed within theorthopedic fixation device 1715 such that the flow channels 1741 are influid communication with the porous coating 1735. A connection port 1745is fluidly connected to the flow channels 1741, the port beingconfigured for connection to a reduced pressure delivery tube 1751 and areduced pressure delivery source 1753. The flow channels 1741 are usedto deliver a reduced pressure to the porous coating 1735 and/or the bonesurrounding the orthopedic fixation device 1715 following fixation ofthe orthopedic fixation device 1715 to the bone 1717. The flow channels1741 may include a main feeder line 1743 that fluidly communicates withseveral lateral branch lines 1747, which communicate with the porouscoating 1735. The lateral branch lines 1747 may be oriented normal tothe main feeder line 1743 as illustrated in FIG. 35, or may be orientedat angles to the main feeder line 1743. An alternative method fordistributing the reduced pressure includes providing a hollow orthopedicfixation device, and filling the inner space of the orthopedic fixationdevice with a cellular (preferably open-cell) material that is capableof fluidly communicating with the porous coating 1735.

The orthopedic fixation device 1715 may be a plate as shown in FIG. 35,or alternatively may be a fixation device such as a sleeve, a brace, astrut, or any other device that is used to stabilize a portion of thebone. The orthopedic fixation device 1715 may further be fasteners usedto attach prosthetic or other orthopedic devices or implanted tissues(e.g. bone tissues or cartilage), provided that the fasteners includeflow channels for delivering reduced pressure to tissue adjacent to orsurrounding the fasteners. Examples of these fasteners may include pins,bolts, screws, or any other suitable fastener.

Referring more specifically to FIG. 36, the orthopedic fixation device1715 may further include a second plurality of flow channels 1761 withinthe orthopedic fixation device 1715 to provide a fluid to the porouscoating 1735 and/or the bone surrounding the orthopedic fixation device1715. The fluid could include filtered air or other gases, antibacterialagents; antiviral agents, cell-growth promotion agents, irrigationfluids, chemically active agents, or any other fluid. If it is desiredto introduce multiple fluids to the bone surrounding the orthopedicfixation device 1715, additional paths of fluid communication may beprovided. A connection port 1765 is fluidly connected to the flowchannels 1761, the port 1765 being configured for connection to a fluiddelivery tube 1771 and a fluid delivery source 1773. The flow channels1761 may include a main feeder line 1783 that fluidly communicates withseveral lateral branch lines 1785, which communicate with the porouscoating 1735. The lateral branch lines 1785 may be oriented normal tothe main feeder line 1783 as illustrated in FIG. 33, or may be orientedat angles to the main feeder line 1783.

The delivery of reduced pressure to the first plurality of flow channels1741 and the delivery of the fluid to the second plurality of flowchannels 1761 may be accomplished by separate tubes such as reducedpressure delivery tube 1751 and fluid delivery tube 1771. Alternatively,a tube having multiple lumens as described previously herein may be usedto separate the communication paths for delivering the reduced pressureand the fluid. It should further be noted that while it is preferred toprovide separate paths of fluid communication within the orthopedicfixation device 1715, the first plurality of flow channels 1741 could beused to deliver both the reduced pressure and the fluid to the boneadjacent the orthopedic fixation device 1715.

The use of orthopedic fixation device 1715 as a manifold to deliverreduced pressure to the area of bone adjacent the orthopedic fixationdevice 1715 speeds and improves recovery of the defect 1719 of the bone1717. Providing the second plurality of flow channels 1761 tocommunicate fluids to the bone surrounding the orthopedic fixationdevice 1715 improves the successful generation of new bone near theorthopedic fixation device.

Referring to FIG. 37, a method 1811 for healing a bone defect of a boneincludes at 1815 fixating the bone using an orthopedic fixation device.The orthopedic fixation device includes a plurality of flow channelsdisposed within the orthopedic fixation device. At 1819, a reducedpressure is applied to the bone defect through the plurality of flowchannels.

Referring to FIG. 38, a method 1911 for administering reduced pressuretissue treatment to a tissue site includes at 1915 positioning amanifold having a plurality of flow channels such that at least aportion of the flow channels are in fluid communication with the tissuesite. A reduced pressure is applied at 1919 to the tissue site throughthe flow channels, and a fluid is delivered at 1923 to the tissue sitethrough the flow channels

Referring to FIG. 39, a method 2011 for administering reduced pressuretissue treatment to a tissue site includes at 2015 positioning a distalend of a manifold delivery tube adjacent the tissue site. At 2019 afluid is delivered through the manifold delivery tube to the tissuesite. The fluid is capable of filling a void adjacent the tissue siteand becoming a solid manifold having a plurality of flow channels influid communication with the tissue site. A reduced pressure is appliedat 2023 to the tissue site through the flow channels of the solidmanifold.

Referring to FIGS. 40-48, a reduced pressure delivery system 2111includes a primary manifold 2115 having a flexible wall 2117 surroundinga primary flow passage 2121. The flexible wall 2117 is connected at aproximal end 2123 to a reduced pressure delivery tube 2125. Since theshape of the reduced pressure delivery tube 2125 will typically be roundin cross-section, and since the shape of the primary manifold 2115 incross-section may be other than round (i.e. rectangular in FIGS. 40-45and triangular in FIGS. 46-48), a transition region 2129 is providedbetween the reduced pressure delivery tube 2125 and the primary manifold2115. The primary manifold 2115 may be adhesively connected to thereduced pressure delivery tube 2125, connected using other means such asfusing or insert molding, or alternatively may be integrally connectedby co-extrusion. The reduced pressure delivery tube 2125 deliversreduced pressure to the primary manifold 2115 for distribution at ornear the tissue site.

A blockage prevention member 2135 is positioned within the primarymanifold to prevent collapse of the manifold 2115, and thus blockage ofthe primary flow passage 2121 during application of reduced pressure. Inone embodiment, the blockage prevention member 2135 may be a pluralityof projections 2137 (see FIG. 44) disposed on an inner surface 2141 ofthe flexible wall 2117 and extending into the primary flow passage 2121.In another embodiment, the blockage prevention member 2135 may be asingle or multiple ridges 2145 disposed on the inner surface 2141 (seeFIGS. 40 and 41). In yet another embodiment, the blockage preventionmember 2135 may include a cellular material 2149 disposed within theprimary flow passage such as that illustrated in FIG. 47. The blockageprevention member 2135 may be any material or structure that is capableof being inserted within the flow passage or that is capable of beingintegrally or otherwise attached to the flexible wall 2117. The blockageprevention member 2135 is able to prevent total collapse of the flexiblewall 2117, while still allowing the flow of fluids through the primaryflow passage 2121.

The flexible wall 2117 further includes a plurality of apertures 2155through the flexible wall 2117 that communicate with the primary flowpassage 2121. The apertures 2155 allow reduced pressure delivered to theprimary flow passage 2121 to be distributed to the tissue site.Apertures 2155 may be selectively positioned around the circumference ofthe manifold 2115 to preferentially direct the delivery of vacuum. Forexample, in FIG. 51, apertures may be placed facing the bone, facing theoverlying tissue, or both.

The reduced pressure delivery tube 2125 preferably includes a firstconduit 2161 having at least one outlet fluidly connected to the primaryflow passage 2121 to deliver reduced pressure to the primary flowpassage 2121. A second conduit 2163 may also be provided to purge theprimary flow passage 2121 and the first conduit 2161 with a fluid toprevent or resolve blockages caused by wound exudate and other fluidsdrawn from the tissue site. The second conduit 2163 preferably includesat least one outlet positioned proximate to at least one of the primaryflow passage 2121 and the at least one outlet of the first conduit 2161.

Referring more specifically to FIGS. 40 and 41, the reduced pressuredelivery system 2111 the second conduit 2163 may include multipleconduits for purging the primary flow passage 2121 and the first conduit2161. While the end of the flexible wall 2117 opposite the end attachedto reduced pressure delivery tube 2125 may be open as illustrated inFIG. 40, it has been found that capping the end of the flexible wall2117 may improve the performance and reliability of the purgingfunction. Preferably, a head space 2171 is provided for between thecapped end of the flexible wall and the end of the second conduits 2163.The head space 2171 allows for a buildup of purge fluid during thepurging process, which helps drive the purge fluid through the primaryflow passage 2121 and into the first conduit 2161.

Also illustrated in FIG. 41 is the divider that serves as the blockageprevention member 2135. The centrally-located divider bifurcates theprimary flow passage 2121 into two chambers, which allows continuedoperation of the primary manifold 2115 if one of the chambers becomesblocked and purging is unable to resolve the blockage.

Referring to FIGS. 49 and 50, a reduced pressure delivery system 2211includes a primary manifold 2215 that is integral to a reduced pressuredelivery tube 2217. The reduced pressure delivery tube 2217 includes acentral lumen 2223 and a plurality of ancillary lumens 2225. While theancillary lumens 2225 may used to measure pressure at or near the tissuesite, the ancillary lumens 2225 may further be used to purge the centrallumen 2223 to prevent or resolve blockages. A plurality of apertures2231 communicate with the central lumen 2223 to distribute the reducedpressure delivered by the central lumen 2223. As illustrated in FIG. 50,it is preferred that the apertures 2231 not penetrate the ancillarylumens 2225. Also illustrated in FIG. 50 is the countersunk end of thereduced pressure delivery tube, which creates a head space 2241 beyondthe end of the ancillary lumens 2225. If tissue, scaffolds, or othermaterials were to engage the end of the reduced pressure delivery tube2217 during application of reduced pressure, the head space 2241 wouldcontinue to allow purging fluid to be delivered to the central lumen2223.

In operation, the reduced pressure delivery systems 2111, 2211 of FIGS.40-50 may be applied directly to a tissue site for distributing reducedpressure to the tissue site. The low-profile shape of the primarymanifolds is highly desirous for the percutaneous installation andremoval techniques described herein. Similarly, the primary manifoldsmay also be inserted surgically.

Referring to FIG. 51, the primary manifolds 2115, 2215 may be used inconjunction with a secondary manifold 2321. In FIG. 51, the secondarymanifold 2321 includes a two-layered felted mat. The first layer of thesecondary manifold 2321 is placed in contact with a bone tissue sitethat includes a bone fracture. The primary manifold 2115 is placed incontact with the first layer, and the second layer of the secondarymanifold 2321 is placed on top of the primary manifold 2115 and firstlayer. The secondary manifold 2321 allows fluid communication betweenthe primary manifold 2115 and the tissue site, yet prevents directcontact between the tissue site and the primary manifold 2115.

Preferably, the secondary manifold 2321 is bioabsorbable, which allowsthe secondary manifold 2321 to remain in situ following completion ofreduced pressure treatment. Upon completion of reduced pressuretreatment, the primary manifold 2115 may be removed from between thelayers of the secondary manifold with little or no disturbance to thetissue site. In one embodiment, the primary manifold may be coated witha lubricious material or a hydrogel-forming material to ease removalfrom between the layers.

The secondary manifold preferably serves as a scaffold for new tissuegrowth. As a scaffold, the secondary manifold may be comprised of atleast one material selected from the group of polylactic acid,polyglycolic acid, polycaprolactone, polyhydroxybutyrate,polyhydroxyvalerate, polydioxanone, polyorthoesthers, polyphosphazenes,polyurethanes, collagen, hyaluronic acid, chitosan, hydroxyapatite,calcium phosphate, calcium sulfate, calcium carbonate, bioglass,stainless steel, titanium, tantalum, allografts, and autografts.

The purging function of the reduced pressure delivery systems 2111, 2211described above may be employed with any of the manifolds describedherein. The ability to purge a manifold or a conduit delivering reducedpressure prevents blockages from forming that hinder the administrationof reduced pressure. These blockages typically form as the pressure nearthe tissue site reaches equilibrium and egress of fluids around thetissue site slows. It has been found that purging the manifold andreduced pressure conduit with air for a selected amount of time at aselected interval assists in preventing or resolving blockages.

More specifically, air is delivered through a second conduit separatefrom a first conduit that delivers reduced pressure. An outlet of thesecond conduit is preferably proximate to the manifold or an outlet ofthe first conduit. While the air may be pressurized and “pushed” to theoutlet of the second conduit, the air is preferably drawn through thesecond conduit by the reduced pressure at the tissue site. It has beenfound that delivery of air for two (2) seconds at intervals of sixty(60) seconds during the application of reduced pressure is sufficient toprevent blockages from forming in many instances. This purging scheduleprovides enough air to sufficiently move fluids within the manifold andfirst conduit, while preventing the introduction of too much air.Introducing too much air, or introducing air at too high of an intervalfrequency will result in the reduced pressure system not being able toreturn to the target reduced pressure between purge cycles. The selectedamount of time for delivering a purging fluid and the selected intervalat which the purging fluid is delivered will typically vary based on thedesign and size of system components (e.g. the pump, tubing, etc.).However, air should be delivered in a quantity and at a frequency thatis high enough to sufficiently clear blockages while allowing the fulltarget pressure to recover between purging cycles.

Referring to FIG. 52, in one illustrative embodiment, a reduced pressuredelivery system 2411 includes a manifold 2415 fluidly connected to afirst conduit 2419 and a second conduit 2423. The first conduit 2419 isconnected to a reduced pressure source 2429 to provide reduced pressureto the manifold 2415. The second conduit 2423 includes an outlet 2435positioned in fluid communication with the manifold 2415 and proximatean outlet of the first conduit 2419. The second conduit 2423 is fluidlyconnected to a valve 2439, which is capable of allowing communicationbetween the second conduit 2423 and the ambient air when the valve isplaced in an open position. The valve 2439 is operably connected to acontroller 2453 that is capable of controlling the opening and closingof the valve 2439 to regulate purging of the second conduit with ambientair to prevent blockages within the manifold 2415 and the first conduit2419.

It should be noted that any fluid, including liquids or gases, could beused to accomplish the purging techniques described herein. While thedriving force for the purging fluid is preferably the draw of reducedpressure at the tissue site, the fluid similarly could be delivered by afluid delivery means similar to that discussed with reference to FIG. 9.

The administration of reduced pressure tissue treatment to a tissue sitein accordance with the systems and methods described herein may beaccomplished by applying a sufficient reduced pressure to the tissuesite and then maintaining that sufficient reduced pressure over aselected period of time. Alternatively, the reduced pressure that isapplied to the tissue site may be cyclic in nature. More specifically,the amount of reduced pressure applied may be varied according to aselected temporal cycle. Still another method of applying the reducedpressure may vary the amount of reduced pressure randomly. Similarly,the rate or volume of fluid delivered to the tissue site may beconstant, cyclic, or random in nature. Fluid delivery, if cyclic, mayoccur during application of reduced pressure, or may occur during cyclicperiods in which reduced pressure is not being applied. While the amountof reduced pressure applied to a tissue site will typically varyaccording to the pathology of the tissue site and the circumstancesunder which reduced pressure tissue treatment is administered, thereduced pressure will typically be between about −5 mm Hg and −500 mmHg, but more preferably between about −5 mm Hg and −300 mm Hg.

While the systems and methods of the present invention have beendescribed with reference to tissue growth and healing in human patients,it should be recognized that these systems and methods for applyingreduced pressure tissue treatment can be used in any living organism inwhich it is desired to promote tissue growth or healing. Similarly, thesystems and methods of the present invention may be applied to anytissue, including without limitation bone tissue, adipose tissue, muscletissue, neural tissue, dermal tissue, vascular tissue, connectivetissue, cartilage, tendons, or ligaments. While the healing of tissuemay be one focus of applying reduced pressure tissue treatment asdescribed herein, the application of reduced pressure tissue treatment,especially to tissues located beneath a patient's skin, may also be usedto generate tissue growth in tissues that are not diseased, defective,or damaged. For example, it may be desired to use the percutaneousimplantation techniques to apply reduced pressure tissue treatment togrow additional tissue at a tissue site that can then be harvested. Theharvested tissue may be transplanted to another tissue site to replacediseased or damaged tissue, or alternatively the harvested tissue may betransplanted to another patient.

It is also important to note that the reduced pressure deliveryapparatuses described herein may be used in conjunction with scaffoldmaterial to increase the growth and growth rate of new tissue. Thescaffold material could be placed between the tissue site and thereduced pressure delivery apparatus, or the reduced pressure deliveryapparatus could itself be made from bioresorbable material that servesas a scaffold to new tissue growth.

It should be apparent from the foregoing that an invention havingsignificant advantages has been provided. While the invention is shownin only a few of its forms, it is not just limited but is susceptible tovarious changes and modifications without departing from the spiritthereof.

We claim:
 1. A method of administering a reduced pressure therapy to atissue site comprising: percutaneously positioning a distal end of amanifold delivery tube adjacent a tissue site; percutaneously deliveringa flowable material through the manifold delivery tube to the tissuesite, the flowable material being capable of filling a void adjacent thetissue site to create a manifold having a plurality of flow channels influid communication with the tissue site; applying a reduced pressure tothe tissue site through the manifold delivery tube and the flow channelsof the manifold.
 2. The method according to claim 1, wherein themanifold is bioresorbable.
 3. The method according to claim 1, whereinthe manifold serves as a scaffold for tissue growth.
 4. The methodaccording to claim 1, wherein the manifold foams and undergoes a phasechange in the presence of at least one of a bodily fluid and a bodilytemperature.
 5. The method according to claim 4, wherein the manifold isa gel.
 6. The method according to claim 1, wherein the manifold furthercomprises a bioresorbable polymer dissolved in a solvent and mixed withsodium bicarbonate and citric acid.
 7. The method according to claim 6,wherein the bioresorbable polymer is one of a polylactide-co-glycolide(PLAGA) polymer and a polyethylene glycol-PLAGA copolymer.
 8. The methodaccording to claim 6, wherein the solvent is methylene chloride.
 9. Themethod according to claim 1, wherein the flowable material is selectedfrom the group consisting of a liquid, a slurry, a suspension, a viscousgel, a paste, a putty, and particulate solids.
 10. The method accordingto claim 1, wherein: the flowable material undergoes a phase change inthe presence of at least one of a bodily fluid and a bodily temperature;and the flowable material includes a poragen that dissolves followingcuring of the flowable material, the dissolution of the poragen creatingthe plurality of flow channels.
 11. The method according to claim 1,wherein the flowable material includes microspheres having a coatingthat is capable of being selectively crosslinked following delivery ofthe flowable material to the tissue site.
 12. The method according toclaim 11, wherein the coating is selectively crosslinked in response toat least one of heat, light, and a chemical.
 13. The method according toclaim 11, wherein the microspheres following crosslinking create theplurality of flow channels.
 14. The method according to claim 1,wherein: the flowable material is selected from the group consisting ofa paste and a putty having an initial viscosity; the viscosity of theflowable material decreases below the initial viscosity in the presenceof shear forces during delivery to the tissue site; and the viscosity ofthe flowable material reverts to the initial viscosity followingdelivery of the flowable material to the tissue site.
 15. A method ofdelivering reduced pressure to a tissue site comprising: inserting adelivery tube percutaneously to a void in the tissue site; delivering amaterial through the delivery tube to the void; forming flow channels insitu in the material; and delivering a reduced pressure to the tissuesite through the delivery tube and the flow channels.
 16. The method ofclaim 15, wherein forming the flow channels comprises hardening thematerial in the void into a solid state.
 17. The method of claim 15,wherein forming the flow channels comprises forming a foam from thematerial in the void.
 18. The method of claim 15, wherein forming theflow channels comprises dissolving poragens in the material.
 19. Themethod of claim 15, wherein forming the flow channels comprisesdissolving sodium chloride in the material.
 20. A method of deliveringreduced pressure to a tissue site, the method comprising: percutaneouslyinserting a delivery tube adjacent a tissue site; percutaneouslydelivering a flowable material through the delivery tube to a voidadjacent to the tissue site, the flowable material adapted to create amanifold in the void having a plurality of flow channels in fluidcommunication with the tissue site; applying a reduced pressure to thetissue site through the delivery tube and the flow channels of themanifold.